.\" (c) 1998 by Abacus Research & Development, Inc. (ARDI)
.\"
.\" This man page is part of the commercial Executor package available
.\" from ARDI <http://www.ardi.com/>.

.TH AppleDouble 5  "April 10, 1998" "Executor 2.0v"
.SH NAME
AppleDouble \- File format Executor uses to store individual Macintosh files on non-Macintosh filesystems
.SH DESCRIPTION
AppleDouble is a specification that allows storing Macintosh files on
non-Macintosh filesystems.
.PP
In Macintosh parlance, files have two
"forks".  Each fork is effectively an independent file that can be
grown or shrunk without affecting the other fork.  The "resource fork has a
pre-defined order built into it.  The "data" fork doesn't.  In
addition to these two forks, each file has extra meta-data that isn't
available under UNIX filesystems, including things like the file
"type" and file "creator".
.PP
AppleDouble format uses two UNIX files for each Macintosh file.  One
file contains the data fork, the other file contains the
meta-information and the resource fork.  The resource fork filename
has a "%" prepended to it to denote the resource fork.  Unfortunately,
special characters in the filename are represented by using "%xx"
where xx is the hexadecimal representation of the ASCII value of the
special character.  This leads to an ambiguity.  Is "%father" a data
fork whose first character is 0xfa, with the remaining characters
being "ther", or is it the resource fork for the file named "father"?
.PP
The Apple spec says that programs should look inside AppleDouble files
to disambiguate.  Consequently, although ARDI does, very few companies
actually implement AppleDouble according to the Apple specification.
Consequently,
.B executor
won't work with non-conforming files, like those produced by
netatalk.  Technically, there's an option to allow
.B executor
to use AppleDouble files using the netatalk naming variation, but
there have been other bugs in netatalk's AppleDouble implementation that
prevented this from being useful.  As Executor/Linux becomes more
popular, we'll take the time to work out the bugs on both netatalk's
and
.B executor's
side and then switch to using netatalk conventions as the default
behavior.  This will be convenient for people who are running
.B executor
on machines that also provide filesystems to Macs via netatalk.
.PP
Apple's specification for AppleDouble is probably available on their
web-site.
.SH FILES
/home/executor - a symlink to /var/opt/executor/share/home

/var/opt/executor/share/home - good place to store AppleDouble files
.SH "SEE ALSO"
\fIexecutor\fP(1)
